The study appears in Wednesday’s Journal of the American Medical Association. It began in 1980, asking healthy, mostly white nurses aged 30 to 55 to fill out periodic questionnaires about lifestyle and risk factors for cancer and heart disease. Follow-up ended in 2008 or when women died or were diagnosed with cancer.

Risks increased by 10 percent for every 10 grams of alcohol consumed daily. That’s equal to a little less than one 12-ounce bottle of beer, a 4-ounce glass of wine or a shot of whiskey. The increasingly elevated risks were a little higher than seen in other research. It made no difference whether the women drank liquor, beer and wine.

The strongest risks were seen with cumulative consistent alcohol use throughout the study. Increased risks also were seen in binge drinkers — women who consumed at least three drinks daily in a typical month. The results do not apply to women who may have partied hard during week-long vacations but otherwise rarely drank, said lead author Dr. Wendy Chen, a researcher at Brigham and Women’s Hospital and Dana-Farber Cancer Institute and an assistant professor at Harvard Medical School.
http://www.cbsnews.com/8301-500165_162-20128877/light-drinking-linked-to-breast-cancer-risk/